Make white molecular particles on the outside and red on the inside?
I'm not sure if reference object in your linked video is done by the same way, but you can try ...

for outer particles - add Solidify modifier to your object
for inner particles - copy outer object, Apply modifier, go to edit mode select one outer vertex, select Linked L, delete, Recalculate Normals Shift+N

Like this you create &quot;inset&quot; object without overlapping particles.

Enable under Collision

Activate Collision with others
Enable under links
Activate Particles linking with others